Asymmetric synthesis of 3-substituted unsaturated prolines from chiral sulfoximine substituted allyl titanium(IV) complexes
作者:Shashi Kant Tiwari、Andreas Schneider、Stefan Koep、Hans-Joachim Gais
DOI:10.1016/j.tetlet.2004.09.062
日期:2004.11
ester 3. Activation of sulfoximines 4a–e and 11a–c through methylation of the sulfoximine group followed by a KF mediated isomerization of the vinyl aminosulfoxonium salts 5a–e and 12a–c, respectively, to the corresponding allyl aminosulfoxonium salt 6a–e and 13a–c, respectively, and a subsequent intramolecular nucleophilic substitution of the allylic aminosulfoxonium group afforded the enantio- and diastereomerically
3-取代的Δ的不对称合成3,4-不饱和脯氨酸7A - ë和3-取代的4-亚甲基脯氨酸14A - Ç从相应的起始γ,δ不饱和α氨基酸4A - ë和11A - Ç,分别描述。氨基酸衍生物4a – e和11a – d是通过相应的磺胺亚胺取代的烯丙基钛(IV)配合物2a – e和10a – d的氨基烷基化获得的分别与Ñ -叔-butylsulfonyl亚氨酸酯3。通过亚砜亚胺基团的甲基化活化亚砜亚胺4a – e和11a – c,然后通过KF介导的乙烯基氨基亚砜氧鎓盐5a – e和12a – c分别异构化为相应的烯丙基氨基亚砜氧鎓盐6a – e和13a – c分别地,以及随后的烯丙基氨基亚砜基团的分子内亲核取代以中等至高收率提供了对映体和非对映体纯的脯氨酸衍生物。